1. Field of the Invention
The present invention relates to a super abrasive cutting saw and, more specifically, to a diamond cutting saw or a CBN cutting saw made by sintering a pressed powder including super abrasives such as fine diamond abrasives, cubic boron nitride or the like around the periphery of an orbicular cutting saw plate.
2. Description of the Prior Art
As such a diamond cutting saw, for example, the following cutting saw may be given.
As one example of the diamond cutting saw, a pressed powder formed into a prescribed shape by pressing a powder including fine diamond abrasives is formed in advance, after forming two pressed powders having a same shape, a steel plate to be formed into a cutting saw plate is inserted between the two pressed powders in a mold and sintered. In the case of this diamond cutting saw, a seam between the two pressed powders is flat and its outer surfaces are also formed substantially with a flat sinter.
The other diamond cutting saw is formed as such that a sheet of pressed powder formed into a prescribed shape with the powder including the fine diamond abrasives in advance is sintered, and at the same time the cutting saw plate is sintered by intruding it into the sintered portion formed by sintering the pressed powder with its thermal expansion, and simultaneously the sinter is fused onto the cutting saw plate.
Among the conventional diamond cutting saws, since the first diamond cutting saw, when forming the pressed powder, requires to form the orbicular pressed powder having a flat surface preparatively, which is joined together to form a diamond layer with the two pressed powders by sintering, some portions in a border between the two opposing pressed powders are lacking diamond abrasives.
Therefore, by forming a sheet of pressed powder in advance, another diamond cutting saw capable of removing disadvantages of the former diamond cutting saw was invented. However, since the larger the diameter and higher the temperature the larger the magnitude of intrusion of the cutting saw plate into the sinter with its thermal expansion, the latter diamond cutting saw is unsuitable for manufacturing a relatively smaller cutting saw or when using the powder having a lower sintering temperature. Also, bonding strength between the sintered diamond and the cutting saw plate is relatively weak, so the latter diamond cutting saw is unsuitable as the cutting saw used under a severe condition.
A primary object of the present invention is, therefore, to provide the super abrasive cutting saw, in which the super abrasives present in all portions of the sinter and a good sharpness is maintained continuously without being worn locally and unevenly, the number of molds is relatively smaller and a manufacturing apparatus can be simplified and a manufacturing process can be separated for mass production, while enabling to manufacture comparatively smaller cutting saws as well as to use the powder having a lower sintering temperature.
The present invention relates to the super abrasive cutting saw comprising the cutting saw plate formed with suitably spaced concave portions around its periphery, and the sinter sticked to the periphery of the cutting saw plate by heating the pressed powder formed with the powder including super abrasives and divided into two to sinter as being pressed, the sinter being formed as such that at a seam of the two sheets of pressed powders, concave and convex portions formed thereon are fused to oppose each other, its border is extended in a zigzag fashion in the direction of thickness of the cutting saw plate, and corresponding to the concave and convex portions, its outer surfaces also show a corrugated shape formed by a series of concave and convex portions.
The super abrasives incorporated in the sinter, such as fine diamond abrasives, or the like, are present at all portions of the sinter, thereby preventing local and uneven wear and retaining even sharpness. This is because the sinter is formed from two masses that are joined together to define a border that extends in a zigzag fashion along the peripheral border of the masses and which zigzags in the direction of the thickness of the cutting saw plate.
Besides, according to the present invention, since the super abrasive cutting saw can be manufactured by preparatively forming the pressed powder divided into two with the powder including the super abrasives such as the fine diamond abrasives or the like in advance, the manufacturing process can be separated into a plurality of processes, so that the super abrasive cutting saw such as the diamond cutting saw can be manufactured in a large quantity. Also, since the super abrasive cutting saw in accordance with the present invention can be manufactured by preparatively forming the two pressed powders, the number of molds used at sintering can be comparatively reduced to prevent complication of the manufacturing molds.
Moreover, since the super abrasive cutting saw in accordance with the present invention can be manufactured by preparing two preparatively formed pressed powders and joining them together in the molds while holding the cutting saw plate therebetween for sintering, and simultaneously bonding also to the cutting saw plate, different from the conventional diamond cutting saw fused to the sinter by the thermal expansion of the cutting saw plate, reliance on the thermal expansion coefficient of the cutting saw plate is not required. Thus, it is possible to manufacture the comparatively smaller cutting saws and to use the powders having a lower sintering temperature.